Levee plan: Wait until after quake

The best way to save the Delta's fresh water from a levee-crumbling earthquake may be to wait until the quake strikes before taking major action, Los Angeles-area water providers have decided.

Alex Breitler

The best way to save the Delta's fresh water from a levee-crumbling earthquake may be to wait until the quake strikes before taking major action, Los Angeles-area water providers have decided.

The Metropolitan Water District recently approved a plan that would repair broken levees after a temblor rather than shoring them up beforehand.

District board members voted to stockpile repair materials at strategic spots around the Delta; then, if a quake occurs, that rock could be used to patch up levees perhaps along the Middle River, creating a sort of pathway channeling fresh water from the central Delta to the export pumps near Tracy.

"It's not ideal," Patterson said Wednesday. "It's not as elegant as our other strategy."

Beefing up levees ahead of time - or installing a barrier to prevent salt water from penetrating the estuary - would take three years and cost anywhere from $330 million to $485 million, district officials said.

The selected plan could cost $50 million to $200 million. The post-earthquake work would take months, during which the export pumps would be shut down. But even six months without pumping is considered "acceptable," compared with three years if no action is taken, according to Metropolitan staff reports.

It's not acceptable to farmer Jim McLeod, who grows walnuts and serves on the board of the Banta-Carbona Irrigation District in Tracy.

"You can't shut those pumps down for six months," McLeod said. "You can't shut them down for a month. Look at what would happen to the economy. It's scary."

There are others interested in the Delta besides Metropolitan, he said. Better to take action now.

McLeod has pushed for building a gate in the west Delta similar to those used in the Netherlands for flood control. The gate could be closed and opened when needed to control salinity in the Delta. But such a gate would be more expensive than the district's plans.

The danger of a magnitude-6.5 earthquake in the Delta was detailed in the months after Hurricane Katrina struck New Orleans. State officials said a quake could cause $30 billion in damage in the Delta; 50 levees could simultaneously fail, flooding 20 islands.

As those islands flood, the water levels in the Delta would drop, drawing in salt water from San Francisco Bay. The pumps would be turned off.

Over time, however, the central Delta would freshen out, allowing officials to take that water and funnel it through the salty south Delta to the pumps, Patterson said.

"We all have a mess on our hands if this happens," he said. "We're looking for how we can be back in business."

The district, which serves 18 million people in the Los Angeles and San Diego areas, plans to seek money for its project from voter-approved Propositions 1E and 84. Its plan would be carried out in cooperation with a similar plan under development by the state.

This is only a temporary solution, Patterson said; the hotly debated construction of a peripheral canal would carry fresh water around the Delta entirely before sending it south.

State officials have put the odds of a big quake in the Delta at 1-in-200 each year, though a report recently released by the Public Policy Institute of California says the odds are roughly 2-in-3 that such a quake or flood will affect the estuary in the next 50 years.